Still slops consist of a by-product derived from the distillation of fermented sugars with the aim of producing alcohol or yeasts. The sugars for distillation may come from vegetable juices (sugar cane, beet, maize, cereals, grapes, etc.), from molasses, which are by-products formed in the production of sugar, or from intermediate honey.
The still slops produced, due to their high organic load, ferment with the greatest of ease, and their fermentation is aerobic; for this reason their BOD (Biochemical Oxygen Demand) load is very high and they consume all the oxygen in their surroundings, destroying the biosystem. For this reason they are listed as highly pollutant waste.
Still slops consist at origin of a significant quantity of water and a small percentage of soluble and insoluble solids.
The insoluble solids are mainly sulphates, such as calcium sulphate or plaster in a greater percentage, potassium sulphate, etc. and some other salts which depend on the starting vegetable material, and also the yeasts which have been used for the fermentation of the sugars.
The Spanish patent ES 2 158 751 discloses a procedure for the preparation of polymeric complexes from effluent by-products of distilleries; these normally consist of still slops.
A high percentage of the soluble solids are of an organic nature; this also depends on the starting vegetable material, but it is usually in the region of 85% to 90%, and these together are a polymeric complex. The remaining percentage is of an inorganic nature, comprised of salts of potassium, manganese, calcium, etc.
The volumes of concentrated still slops produced in distilleries are very high and require important and highly costly logistics using tanks; all of this makes their use in locations some distance from the point of production unprofitable.
In practice, it may be seen that manipulation of the concentrated liquid still slops is difficult, basically because it requires storage tanks at the locations at which it is desired to carry this out, and it entails, apart from the drawbacks derived from costly outlays and the handling of a viscous liquid (between 180 and 250 cps), the latent danger of contamination of the liquid by a yeast spore or by any bacteria.
Still slops, due to their pH—approximately 4.5— and their organic acids, are corrosive, and require preferably stainless steel tanks, which entails a heavy outlay, as carbon steel tanks have a relatively short life as they are destroyed by the heavy corrosion, or require highly expensive maintenance as they must be cleaned thoroughly and coated with special paints every few years.
It should be highlighted that concentrated still slops are organic matter in their vast majority, and although in strong concentrations contamination by bacteria, fungi and yeast does not spread easily, effects as simple as warm temperatures and condensation in the storage tanks can unleash heavy contamination which spreads in a short time interval.
This contamination first generates heavy emissions of carbon dioxide, and thick layers of fungi on the surfaces of the tanks. When the contaminated liquid is used, the bacteria contained in the same spread to the locations where the liquid is applied.
The only way of preventing these contaminations is by means of the use of potent biocides, which are highly costly, and the majority of which are to be banned due to their carcinogenic characteristics (formol, for example) and another particularity is that their effects are short-term and it is necessary to repeat their application frequently.
On the other hand, concentrated liquid still slops tend to decant their dissolved solids which flocculate constantly, and to deposit their organic matter on the base of the tank, creating a sludge which is rich in organic matter; this makes it very difficult for the richness or characteristics of the liquid to be constant and known. This richness or uniformity of content varies in accordance with the height of the tank, the time the still slops have been stored, the ambient temperature, etc. and the consequence is that at different layers or levels in the tank the characteristics of the still slops are different. Accordingly, the handling of these still slops stored in a vessel is banned at well-defined formulations. They are only valid for blends in proportions in which the variations in this component are not of great importance as they are applied in flood irrigation or similar applications.
Furthermore, concentrated liquid still slops contain a percentage of water of approximately 50%, which prevents their use for the majority of formulations.
The aforementioned difficulties regarding transport, storage, preservation and formulation prevent the use of concentrated liquid still slops in a host of applications which would represent a practical, productive use for this product; among these the following may be highlighted:                Uses in industry as textile colorants, in leather as tanning agents and colorants, etc.        Uses in agriculture accompanying crystalline-soluble fertilisers and chemical granules, among others.        Uses as an enhancer of animal food absorption, for example in pig farms.        Uses in human nutrition in hot and cold food and drinks, likewise in medicine for easing intestinal functions, among other uses.        
With regard to the drying of the still slops, likewise the powder produced when hot and damp, there must be no contact between the powder and any artefact not at speed, as the powder will be deposited on it and will adhere firmly, subsequently collecting the powder which continues to arrive. The powder must be in continuous movement and must, during its journey or transport in motion, be dried and cooled, which requires that there shall not be artefacts which interrupt its speed until its temperature and humidity so permit.
It is well-known that a cyclone consists of a body in the shape of an inverted cone, into which an air draught enters tangentially, carrying the powder. A downward air draught, also called cyclone, is generated towards the vertex of the cyclone, and the solid particles descend, sliding down the wall, while spinning at great speed. When the cyclone-shaped air draught reaches the bottom or zone of the vertex of the cone, it is absorbed upwards by the cyclone at the centre or axis of the cone. It is necessary for cyclones to be closed at the bottom in order to prevent the entry of air which would be sucked by the cyclone and which would draw the powder towards the top and out of the cyclone, preventing collection of the powder.
If the bottom of the artefact or zone of the vertex is closed or features a closed tray connected at this point, the powder falls into the tray and the air moves upward at the centre of the artefact and exits at the top towards an evacuation flue.
In the case of the still slops, if the cyclone were to have at its base a closed tray or a rotary shut-off valve, the powder would be halted and, due to being in contact with the device or the tray, would become compacted, producing a block of hard, compacted powder which would eventually block the cyclone, and should the powder not be removed, it would be drawn up to the flue by the air draught.